Observing the atmospheric evolution of ozone-depleting substances

Abstract. A stratosphere-resolving configuration of the Met Office's Unified Model (UM) with the United Kingdom Chemistry and Aerosols (UKCA) scheme is used to investigate the atmospheric response to changes in (a) greenhouse gases and climate, (b) ozone-depleting substances (ODSs) and (c) non-methane ozone precursor emissions. A suite of time-slice experiments show the separate, as well as pairwise, impacts of these perturbations between the years 2000 and 2100. Sensitivity to uncertainties in future greenhouse gases and aerosols is explored through the use of the Representative Concentration Pathway (RCP) 4.5 and 8.5 scenarios. The results highlight an important role for the stratosphere in determining the annual mean tropospheric ozone response, primarily through stratosphere–troposphere exchange (STE) of ozone. Under both climate change and reductions in ODSs, increases in STE offset decreases in net chemical production and act to increase the tropospheric ozone burden. This opposes the effects of projected decreases in ozone precursors through measures to improve air quality, which act to reduce the ozone burden. The global tropospheric lifetime of ozone (τO3) does not change significantly under climate change at RCP4.5, but it decreases at RCP8.5. This opposes the increases in τO3 simulated under reductions in ODSs and ozone precursor emissions. The additivity of the changes in ozone is examined by comparing the sum of the responses in the single-forcing experiments to those from equivalent combined-forcing experiments. Whilst the ozone responses to most forcing combinations are found to be approximately additive, non-additive changes are found in both the stratosphere and troposphere when a large climate forcing (RCP8.5) is combined with the effects of ODSs.

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Planetary Magnetic Fields and Solar Forcing: Implications for Atmospheric Evolution

Space Science Reviews ◽

10.1007/s11214-007-9176-4 ◽

2007 ◽

Vol 129 (1-3) ◽

pp. 245-278 ◽

Cited By ~ 95

Author(s):

Rickard Lundin ◽

Helmut Lammer ◽

Ignasi Ribas

Keyword(s):

Magnetic Fields ◽

Solar Forcing ◽

Atmospheric Evolution ◽

Planetary Magnetic Fields

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Roles of ozone depleting substances and solar activity in observed long-term trends in total ozone column over Indian region

International Journal of Remote Sensing ◽

10.1080/01431161.2017.1333654 ◽

2017 ◽

Vol 38 (18) ◽

pp. 5091-5105 ◽

Cited By ~ 2

Author(s):

Bikram Sen Sahu ◽

Ankit Tandon ◽

Arun K. Attri

Keyword(s):

Solar Activity ◽

Total Ozone ◽

Indian Region ◽

Total Ozone Column ◽

Long Term Trends ◽

Ozone Depleting Substances ◽

Ozone Column

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Changing trends and emissions of hydrochlorofluorocarbons and their hydrofluorocarbon replacements

10.5194/acp-2016-977 ◽

2016 ◽

Author(s):

Peter G. Simmonds ◽

Matthew Rigby ◽

Archibold McCulloch ◽

Simon O'Doherty ◽

Dickon Young ◽

...

Keyword(s):

Growth Rates ◽

Montreal Protocol ◽

Hfc 134A ◽

Production And Consumption ◽

Ozone Depleting Substances ◽

Phase Out ◽

Article 5 ◽

The Impact ◽

Global Emissions

Abstract. High frequency, in situ global observations of HCFC-22 (CHClF2), HCFC-141b (CH3CCl2F), HCFC-142b (CH3CClF2) and HCFC-124 (CHClFCF3) and their main HFC replacements HFC-134a (CH2FCF3), HFC-125 (CHF2CF3), HFC-143a (CH3CF3), and HFC-32 (CH2F2) have been used to determine their changing global growth rates and emissions in response to the Montreal Protocol and its recent amendments. The 2007 adjustment to the Montreal Protocol required the accelerated phase-out of HCFCs with global production and consumption capped in 2013, to mitigate their environmental impact as both ozone depleting substances and important greenhouse gases. We find that this change has coincided with a reduction in global emissions of the four HCFCs with aggregated global emissions in 2015 of 444 ± 75 Gg/yr, in CO2 equivalent units (CO2 e) 0.75 ± 0.1 Gt/yr, compared with 483 ± 70 Gg/yr (0.82 ± 0.1 Gt/yr CO2 e) in 2010. (All quoted uncertainties in this paper are 1 sigma). About 80 % of the total HCFC atmospheric burden in 2015 is HCFC-22, where global HCFC emissions appear to have been relatively constant in spite of the 2013 cap on global production and consumption. We attribute this to a probable increase in production and consumption of HCFC-22 in Montreal Protocol Article 5 (developing) countries and the continuing release of HCFC-22 from the large banks which dominate HCFC global emissions. Conversely, the four HFCs all show increasing annual growth rates with aggregated global HFCs emissions in 2015 of 329 ± 70 Gg/yr (0.65 ± 0.12 Gt/yr CO2 e) compared to 2010 with 240 ± 50 Gg/yr (0.47 ± 0.08 Gt/yr CO2 e). As HCFCs are replaced by HFCs we investigate the impact of the shift to refrigerant blends which have lower global warming potentials (GWPs). We also note that emissions of HFC-125 and HFC-32 appear to have increased more rapidly during the 2011–2015 5-yr period compared to 2006–2010.

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Future Changes in the Ozone Quasi-Biennial Oscillation with Increasing GHGs and Ozone Recovery in CCMI Simulations

Journal of Climate ◽

10.1175/jcli-d-16-0464.1 ◽

2017 ◽

Vol 30 (17) ◽

pp. 6977-6997 ◽

Cited By ~ 4

Author(s):

Hiroaki Naoe ◽

Makoto Deushi ◽

Kohei Yoshida ◽

Kiyotaka Shibata

Keyword(s):

Zonal Wind ◽

Climate Model ◽

Vertical Shear ◽

Quasi Biennial Oscillation ◽

The Past ◽

Meteorological Research Institute ◽

Climate Simulations ◽

The Future ◽

Ozone Depleting Substances ◽

Biennial Oscillation

The future quasi-biennial oscillation (QBO) in ozone in the equatorial stratosphere is examined by analyzing transient climate simulations due to increasing greenhouse gases (GHGs) and decreasing ozone-depleting substances under the auspices of the Chemistry–Climate Model Initiative. The future (1960–2100) and historical (1979–2010) simulations are conducted with the Meteorological Research Institute Earth System Model. Three climate periods, 1960–85 (past), 1990–2020 (present), and 2040–70 (future) are selected, corresponding to the periods before, during, and after ozone depletion. The future ozone QBO is characterized by increases in amplitude by 15%–30% at 5–10 hPa and decreases by 20%–30% at 40 hPa, compared with the past and present climates; the future and present ozone QBOs increase in amplitude by up to 60% at 70 hPa, compared with the past climate. The increased amplitude at 5–10 hPa suggests that the temperature-dependent photochemistry plays an important role in the enhanced future ozone QBO. The weakening of vertical shear in the zonal wind QBO is responsible for the decreased amplitude at 40 hPa in the future ozone QBO. An interesting finding is that the weakened zonal wind QBO in the lowermost tropical stratosphere is accompanied by amplified QBOs in ozone, vertical velocity, and temperature. Further study is needed to elucidate the causality of amplification about the ozone and temperature QBOs under climate change in conditions of zonal wind QBO weakening.

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Addendum: Substantial twentieth-century Arctic warming caused by ozone-depleting substances

Nature Climate Change ◽

10.1038/s41558-020-0711-6 ◽

2020 ◽

Vol 10 (2) ◽

pp. 167-167

Author(s):

L. M. Polvani ◽

M. Previdi ◽

M. R. England ◽

G. Chiodo ◽

K. L. Smith

Keyword(s):

Twentieth Century ◽

Arctic Warming ◽

Ozone Depleting Substances

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Chemical and climatic drivers of radiative forcing due to changes in stratospheric and tropospheric ozone over the 21<sup>st</sup> century

10.5194/acp-2017-741 ◽

2017 ◽

Author(s):

Antara Banerjee ◽

Amanda C. Maycock ◽

John A. Pyle

Keyword(s):

Greenhouse Gas ◽

Tropospheric Ozone ◽

Radiative Forcing ◽

Climate Model ◽

Stratospheric Ozone ◽

Radiative Forcings ◽

Climatic Drivers ◽

Ozone Precursor ◽

Ozone Depleting Substances ◽

Projected Changes

Abstract. The ozone radiative forcings (RFs) resulting from projected changes in climate, ozone-depleting substances (ODSs), non-methane ozone precursor emissions and methane between the years 2000 and 2100 are calculated using simulations from the UM-UKCA chemistry-climate model. Projected measures to improve air-quality through reductions in tropospheric ozone precursor emissions present a co-benefit for climate, with a net global mean ozone RF of −0.09 Wm−2. This is opposed by a positive ozone RF of 0.07 Wm−2 due to future decreases in ODSs, which is mainly driven by an increase in tropospheric ozone through stratosphere-to-troposphere exchange. An increase in methane abundance by more than a factor of two (as projected by the RCP8.5 scenario) is found to drive an ozone RF of 0.19 Wm−2, which would greatly outweigh the climate benefits of tropospheric non-methane ozone precursor reductions. A third of the ozone RF due to the projected increase in methane results from increases in stratospheric ozone. The sign of the ozone RF due to future changes in climate (including the radiative effects of greenhouse gas concentrations, sea surface temperatures and sea ice changes) is shown to be dependent on the greenhouse gas emissions pathway, with a positive RF (0.06 Wm−2) for RCP4.5 and a negative RF (−0.07 Wm−2) for the RCP8.5 scenario. This dependence arises from differences in the contribution to RF from stratospheric ozone changes.

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Characterization of secondary organic aerosol from heated-cooking-oil emissions: evolution in composition and volatility

Atmospheric Chemistry and Physics ◽

10.5194/acp-21-5137-2021 ◽

2021 ◽

Vol 21 (6) ◽

pp. 5137-5149 ◽

Cited By ~ 1

Author(s):

Manpreet Takhar ◽

Yunchun Li ◽

Arthur W. H. Chan

Keyword(s):

Gas Phase ◽

Organic Compounds ◽

Secondary Organic Aerosol ◽

Carbon Number ◽

Complex Mixture ◽

Organic Aerosol ◽

Oxidation Products ◽

Atmospheric Evolution ◽

Oxidative Aging ◽

Cooking Oil

Abstract. Cooking emissions account for a major fraction of urban organic aerosol. It is therefore important to understand the atmospheric evolution in the physical and chemical properties of organic compounds emitted from cooking activities. In this work, we investigate the formation of secondary organic aerosol (SOA) from oxidation of gas-phase organic compounds from heated cooking oil. The chemical composition of cooking SOA is analyzed using thermal desorption–gas chromatography–mass spectrometry (TD–GC–MS). While the particle-phase composition of SOA is a highly complex mixture, we adopt a new method to achieve molecular speciation of the SOA. All the GC-elutable material is classified by the constituent functional groups, allowing us to provide a molecular description of its chemical evolution upon oxidative aging. Our results demonstrate an increase in average oxidation state (from −0.6 to −0.24) and decrease in average carbon number (from 5.2 to 4.9) with increasing photochemical aging of cooking oil, suggesting that fragmentation reactions are key processes in the oxidative aging of cooking emissions within 2 d equivalent of ambient oxidant exposure. Moreover, we estimate that aldehyde precursors from cooking emissions account for a majority of the SOA formation and oxidation products. Overall, our results provide insights into the atmospheric evolution of cooking SOA, a majority of which is derived from gas-phase oxidation of aldehydes.

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Global Experimentalist Governance

British Journal of Political Science ◽

10.1017/s0007123414000076 ◽

2014 ◽

Vol 44 (3) ◽

pp. 477-486 ◽

Cited By ~ 98

Author(s):

Gráinne De Búrca ◽

Robert O. Keohane ◽

Charles Sabel

Keyword(s):

Problem Solving ◽

Peer Review ◽

Montreal Protocol ◽

International Organization ◽

Transnational Governance ◽

Experimentalist Governance ◽

Ozone Depleting Substances

This article outlines the concept of Global Experimentalist Governance (GXG). GXG is an institutionalized transnational process of participatory and multilevel problem solving, in which particular problems (and the means of addressing them) are framed in an open-ended way, and subjected to periodic revision by various forms of peer review in light of locally generated knowledge. GXG differs from other forms of international organization and transnational governance, and is emerging in various issue areas. The Montreal Protocol on ozone-depleting substances is used to illustrate how GXG functions. The conditions for the emergence of GXG are specified, as well as some of its possible benefits.

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